Africa. In an
uncivilized society, like that of Zululand, they prevent such
cohesion ever taking place. They help to keep the Kaffir tribes
in perpetual unrest and barbarism, by destroying the germs of
civilization and preventing its growth."[647] That the two have
this effect in common may very probably be true, but in many
respects they are antagonistic to each other. Slavery meets the
necessity for many laborers which may otherwise be a cause for
polygamy. Wherever slavery exists it affords striking
illustrations of the tendency of the mores towards consistency
with each other, and that means, of course, their tendency to
cluster around some one or two leading ones. Africa now furnishes
the leading proofs of this. The negro society is one in which
physical force is the chief deciding element. The negroes have
enslaved each other for thousands of years. Very few of them have
ever become slaves to whites without having been previously
slaves to other negroes. In 1875 it was reckoned that twenty
thousand persons, chiefly women and children whose male relatives
had generally been killed, were taken into slavery from around
Lake Nyassa. The difficulties and expense of the slave trade in
that region became so great that it could not be carried on
except by alliance with one tribe which defeated and enslaved
another and sold the survivors. The Arabs opened paths for ivory
hunting. The slave dealers used these means of communication.
They established garrisons in order to exploit the territory, and
ended by depopulating it.[648] Junker argues earnestly against
the impression which has been established in Europe that Arabs
are chiefly to blame for slavery. "There are places in Africa
where three men cannot be sent on a journey together for fear
two of them may combine and sell the third."[649]

+274. Some men serving others. Freedom and equality. Figurative
use of "slavery."+ Must we infer, then, that there is a social
necessity that some men must serve others? In the New Testament
it is taught that willing and voluntary service of others is the
highest duty and glory of human life. If one man's strength is
spent on another man's struggle for existence, the survival of
the former in the competition of life is impaired. The men of
talent are constantly forced to serve the rest. They make the
discoveries and inven